The invention concerns an electrical machine, specifically a rectifier-energized synchronous machine on the transversal flow principle. A machine designed according to this operating principle is known from DE-PS 37 05 089.
The so-called transversal flow concept is based on exciting the stator field not in the longitudinal direction of the machine--i.e., parallel to the axis of rotation of the rotor--but in peripheral direction, that is, along the direction of movement as the rotor rotates. To that end, the rotor has at least a pole structure of two side-by-side rows of permanent magnets alternately magnetized in peripheral direction and soft iron elements, the two rows being separated by an intermediate layer of magnetically and electrically nonconductive material. In principle, this pole structure is of drum shape.
The stator consists essentially of two parts, namely an outer stator arranged radially outside the pole structure and an inside stator arranged radially within the pole structure. Each stator part features soft iron armature elements which essentially are fashioned U-shaped and whose open shanks are opposed in magnets of the rotors, from radially inside or radially outside, across an air gap. The prior machine features for excitation, for each stator part, an annular winding extending in peripheral direction.
With this arrangement characterized by a simple winding structure and with a direction of magnetic flux extending transverse to the direction of movement, high power densities can be achieved, especially when selecting small pole pitches. The electrical lead to the two annular windings of the stator halves must be passed through the armature elements. For removal of the heat accuring in the windings there are as well only the spaces between the armature elements available. On the inside stator, however, the spaces between the armature elements are at identical pole number and smaller radius considerably smaller than on the outside stator. Thus, the space conditions are especially unfavorable for the inside stator, entailing problems in the feed line design, winding structure and assembly of the inside stator.